System of telegraph distribution



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SYSTEIVI 0F TELEGRAPH DISTRIBUTION.

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SYSTEM 0F TELEGRAPH DISTRIBUTION.

APPLICATION FILED FEB. 5.1920.

Patented June 113, i922.

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SYSTEM 0F TELEGRAPH DISTRIBUTION.

APPLICATION FILED FEB. 5| 1920.

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SYSTEM OF TELEGRAPH DISTRIBUTION.

APPLICATION FILED FEB. 5. |920.

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SYSTEM 0F TELEGRAPH DISTRIBUTION.

APPLICATION FILED FEB. 5. 1920..

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SYSTEM OF TELEGRAPH DISTRIBUTION.

APPLICATION FILED FEB. 5. 1920.

Patented June IIS, i922.

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L. IVI. POTTS.

SYSTEM 0F TELEGRAPH DISTRIBUTION.

APPLICATION FILED FEB. 5| 1920.

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.L '.WIIIIII ATTORNEY.

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SYSTEM 0F TELEGRAPH DISTRIBUTION.

APPLICATION FILED FEB. 5

Patented June 1?., 1922..

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LOUIS M. POTTS, 11 BALTIMORE, MARYLAND, ASSIGNOR, BY MESNE ASSIGNMENTS, TO AMERICAN TELEPHONE AND TELES-BAPE COMPANY, OF NEW YORK, N. Y., A

'CORPQRTION 40F NEW YORK.

SYSTEM OF TELEGRAPH DISTRIBUTION.

Laietana. y

Specification of Letters Patent.

Patented June 1S, 11922.

Application filed February 5, 1920. Serial No. 356,513.

,T 0 all who m t may con-cern Be it known that l, Louis M. Porre, a

citizen of the United States of America, re-

. the time interval of a single signal.

. have siding at Baltimore, State of Maryland, have invented certain new and useful llmprovements in Systems of Telegraph Distribution, of which the following is a speciication. i

In my copending application 286,540 l described a similar system. The present system is an improvement in that it uses at the substations a met-al storage device, an improved form of that described in my U. S. Patent No.-1,258,809, and also uses mechanical selecting device similar to that described in my U. S. Patents Nos. 1,229,201 and 1,229,202. By this method the system is more practical for use in offices when skilled attendants are not available, by not requiringl perforating mechanism or tape. The mechanical nature of all the apparatus at the substation also makes possible maintenance by a systemof inspection and vrepairs can be made by typewriter or adding machine repairmen. Due to the use of the metal storage at thesubstation and direct repeating from relays at central. the lag between the depression'of a key and the printinfr of the corresponding character at the su station may be approximately equal to This is a point of great impp-rtancein private wire service, especially'for stock brokers.

This invention relates to improvements in systems of telegraph distribution and-re- 'w lates particularly to the use of a single trunk line by several subscribers for independent 'communica-tion between selected .pairs -of stations.

rlhe invention contemplates operating the trunk line in multiplex by a synchronous method and operating-the branch lines connecting the subscriberto the central ofiice `bya 'method not involving continuously synchronized apparatus. The apparatus describedl also includes novel methods of repeating -and improved methods of operable importance in a system .of this kind since the substations may be located at points where skill is lacking for the maintenance of any apparatus not absolutely essential.

In describing my said invention reference will be made to the accompanying drawings in whichi Fig. 1 is a skeleton side elevation of the storing and transmitter controlling device at the substation.

F 1g. 1A is a detail view of the pivot of the circuit controller arms.

Fig. .2 is a detail of the storage spacing device in section on line CC Figft. I

Fig. 3 is a detail of the storage restoring device in section on line BB Fig. 6.

Fig. 4. -is a detail of the transmitter controlling element spacing pawls in section on line AA Fig. 1.

Fig. 5 shows a fragment of key lever and a slide bar.

Fig. 6 is a View partly in section showing the relation of certain parts in the storage device and transmitting device at the substation.

F 7 shows the roller clutch control in section partly on line FF and partly on line HH Fig. G.

8 is a view of the roller clutch in section on line GG Fig. 6.

Fig. 9 is a view looking down and shows the relation 0f the combination bars in the keyboard and the storage setting levers.

Fig. 10 .is a detail of the friction clutch.

F 1l 1s a detail of the friction clutch.

Fig. 12 is a section of the friction clutch on line EE.

Fig 13 shows the relation of the cams on the escapeinent shaft.

' F ig. 14 is a skeleton view partly in section looking up from belowI of the storage device and transmitter mechanism.

Fig. 15 is a detail' of the transmitter controlling device.

.-F ig. 16 is a View of part of the transmitter controlling'element operating levers.

` Fig. 17 shows the transmitting contacts and one operating element at the substation. The operating element is a section on line 1I ing. ii. o

Fig. 18 is a view of the contact and its operating mechanism at the substation.'

Fig. 19 is a' plan view of the start control from the storage member.

-Fig 20 is 'a view of the start controlfrcm l the storage device, in the position occupied when signals are stored in section on line JJ Fig. 14.

Fig. 21 is similar to Fig. 2() when no signals are stored.

Fig. 22 shows the balance and escapement in section on line DD Fig. 6.

Fig. 23 is a fragmentary view from above of the start arm on the magnet armature.

Fig. 24 shows the balance start mechanism.

Fig. 25 shows the roller clutch which controls the spacing of the transmitter controlling member.

Fig. 26 shows the release mechanism Jfor the roller clutch shown in Fig. 25.

Fig. 27 shows the gear train.

Fig. 28 shows a sectional view of the 1e ceiving selector at central.

Fig. 29 is a skeleton front view of the selector shown in Fig. 28.

Fig. 30 is a skeleton view ofpart of transmitting selector at central.

Fig. 31 is a sectional view of the trans mitting selector at central.

Fig. 32 shows part of the receiving selector at central in the operation of setting an element.

Fig. 33 shows part of the transmitter controlling member at the substation in the act of stepping to the next signal.

Fig. 34 is an. electrical diagram of transmission irom a substation to central and retransmission on a trunk line.

Fig. 35 is an electrical diagram of reception of ysignals from a trunk line and retransmission on a branch line and reception at the substation.

Fig. 36 is a diagram of a double vmultiplex distributed to two sulastations.

Fig. 37 shows the timeintervals on a trans- AInitlting branch.

F ig.n38 shows the current corresponding to a signal composed of the BE combination on a transmitting branch.

Fig. 39 shows the time intervals on the trunk line.

Fig. l0 shows' the current lon the trunk line when no signals are being transmitted.

Fig. 41 shows the saine-signal as shown -in Fig. 33 on the trunk line.

Fig. 42 shows the time intervals on the receiving'branch line.

Fig. 4&3 shows the same signal as Fig. 41 on the receiving branch line.

00de. i

rThe code used is a live unit code usually known as the Baudet code. Such a code is described in my lU. S. Patent 1,229,202. @n the trunk line reversed current is used, and the reversals orn line current due to the code signals are used to keep in phase the apparatus at the two `ends of the line. Dil

ters into the corresponding signal.

iaiafioe ferent channels ot the multiplex normally send to line different polarities so that even when no code signals are being transmitted, there are current reversals on the line for phase control. 0n the branch lines each code signal is preceded by a start7 impulse which acts to keep the apparatus at the end ot' the branch line in phase. j

rllhe transmitting apparatus (see Fig. 1) comprises a series of key levers 1 corresponding in number to the number of different code signals to be transmitted. Key levers 1 are pivoted at a point 2, and at their extreme ends 3, keys levers 1 move in slots in bar 4. lln a hole in bar 4 above each key is a helical compression spring 5, pressing its upper end against lid 6 and its lower end aga-inst tip 3 ot lever 1 and acting to return key lever 1 to normal after the linger has been removed from key tip 7. Above the ends of key levers l are mounted live bars 8a to 8e and a start bar 9. The bars 8- to 8e correspond to the five elements of the code and have cut on their under surface opposite each key lever a right sloping face 1-0 or a left sloping face 11 (see Fig. according to whether or not that particular element en- Bar 9, called the start7 bar has a left sloping face opposite eachl of the key levers 1 and is thrust to the left upon the depression of any key and returns as soon as the linger is removed from a key tip 7. The bars 3a to 8e and bar 9 are mounted for sliding motion at right angles to the direction of key levers 1. rlrhe bars 8a to 8e when the eXtreme lett, have their tips extending under the tips of a series of bell cranks 12a to 12e (see Fig. 9). When slides 8a to 8e are moved to the right their tips are removed from under the tips of bell cranks 12,a to 12e. The bell cranks 12a to 12e have a series of projections 13L to 13e (see Fig. 1) which normally rest against the high part ofa 'cam 14 so that their tips just clear the tops of slide bars 8 to 8e. *Cam 14.- is mounted rigidly on a shaft 15. @n the outer end of shaft 15 is mounted a roller friction clutch (see Figs. 6, 7 and 8) comprising a drum 16 mounted for rotation on a round sleeve 17 fast to shaft 15. Drum 16 carries on its outer end spurgear 18 (see Fig. 27)which meshes with the train of gears 19, gear 20, gear 21 to pinion 22 mounted on shaft 23 of electric motor (see Fig. 6). Electric motor 24 is in c=ony tlnuous operation and through the gears arm 27 having projections 23 and 29 which extend into the space between drum lo and eccentric 25 and carry `1`olle-r 30. Un the side of carrier 2T opposite projections and 29 isla lug '3l adapted to engage tip 32 of bell crank 33 which is held into engagement therewith under tension of spring 34, A Washer 34a on shaft 15 has a projection 34b Which serves as an attachment for one end of spring 38. Washer 34.n also has another projection 34c which serves to prevent the shaft 15 from overthrowing when the clutch' is released. rllhis is accomplished by projection 34C engaging one face of the carrier 3l which is in turn stopped by lug 32. rll`he end oit bell crank 33 rests on one end of another bell crank 35 piycted about point 36. The other arm of bell crank 35 engages the tip 37 of startslide 9. llVhen any key l is operated start slide 9 will be pushed to the left and through bell crank 35 will disengage the tip 32 of bell crank 33 from lug 31 and under tension of spring 38 carrier 27 Will move roller 30 into the narrower portion of the space between eccentric Q5 and drum16 and thereby lock drum 1G to eccentric 25, and since drum 16 is rotating eccentric 25 will in turn rotate and carry With it shaft l5. When shaft- 15 in its ro-y tation carries cam 14 (see Fig. 1) to the position Where the high part passes from under projections 13'@1 and 13e on bell cranks 12a and l2e they will turn about their pivot 39 under tension of springs 40a and 40e and those bell cranks 12a and 12e, Which do not enter into the combination set by the particular key lever 1 depressed, Will move only a short distance until their tips engage the tips of slide bars 8a to 8e. Those bell cranks l2n to 12e, however, which do enter into the particular combination will be permitted to move further. Their tips 41a to 41e in the latter case will strike the tops of corresponding cotter pins 42. rlhe cotter pins 42 are mounted insuccessive groups of five, equally spaced around the circumference of a cylinder 43. Cylinder 43 is mounted on discs 44 adapted to turn on rods 45. By this arrangement cylinder 43 'is free to rotate'yet the space inside is perfectly clear for the transmitter control mechanism described later. Cylinder 43 has on its inner circumference a' series of five circumferential grooves 46 (see Fig. 14). On the o-uter sur face of cylinder 43 is a series of slots 47 parallel With the axis of cylinder 43 and just deep enough to meet the circumferential grooves on the inside of the cylinder. lt will be noted that byvthis arrangement there will be successive groups of five square holes around the cylinder. nto each of these openings is placed a Cotter pin 42., rlhe Cotter pins are spread and made of spring material so that they may be slid toward or away from the aXis of cylinder and "ii in the position "i: which they a ll'heu thev bell ranks l2 to 1; have been allowed to operate as J described 'their tips 4la to eilt i cotti-ir pins and will push them into i, ir inner position in combination roi'- i'esponding to the key l depressed. .fis shaft l5 continues to rotate cani i4 will return bell cranks 12a to l2@ to their normal position. .Sit the same time cam 48 (see Fig. 3) also mounted on shaft l5, will engage a projection 49 on lever 50, also pivoted about pin 39e and will cause its upper end 5l. which extends completely across cylinder 43, to engage the inner ends of the row of cotter pins 552i, which immediately precedes the row 42, and will push all live Cotter pins in this row to their outer position ready to be set for the next signal.

lllhen shaft 15 has completed about Ione half revolution (see Fig. T) lug 31 will engage projection 53 on bell crank 33, if the finger has not been removed from key tip 7., and thus stop the rotation of shaft l5. l/lfhen the finger is removed from key tipI 7, bell crank 33, under tension of spring 34, will move and release projection 53 from lug 31 and allow shaft 15 to continue its rotation. The action just described permits shaft 15 to make only onerevolution no matter how long key l may be held down.

As shaft 15 continues its rotation after lug 3l passes projection arm 50 Will fall off the high part of cam 48 (see Fig. 3) and return to normal under tension otl spring At the same time (see Fig. 2)v lever will be engaged by the rising part of cam 56 and moved to the left. Lever will carry with it pawl 57, which engages a tooth of ratchet wheel 58 under tension of spring Ratchet Wheel 58 is rigidly attached to cylinder 43 and has the same number of teeth as there are groups of Cotter pins 42. As lever is moved by cani 56 ratchet Wheel 58 will be moved forward one space, so that the next row of Cotter pins will be in alignment With tips 41l to 41C. .lust as lug 31 (see yFig. 7) engages tip 32 of bell crank 33 arm 55 will fall olf the high part of cam 56 (see Fig. 2) and under tension of spring '80, pawl 57 Will move to the right and engage the next tooth of ratchet Wheel 53, shaft 15 comes to rest, and all the parts have been returned to normal ready to start on another cycle for the next signal.

When cylinder 43 is advanced as just described it does sol against the tension' of a spring 61 (see Fig. 15), the function of which will be described later. l/Vhen pawl 57 is moving to engage the nexttooth in ratchet Wheel 58 cylinder 43 is prevented from rotating backwards by means of holding pawl 62 which is presse-1l by spring (i3 into engagement with rat-ch t wheel 53. By the continued operation oi ley levers 1 suc cessive groups of cotter pins t2 will be set in combinations corresponding to the successive characters-to be transmitted.

Hawing| described the method by which cot-ter pins l2 are set according to the signals to be transmitted, the method by which these pins control the transmission of the signals will now be described... @n the inside ot cylinder 13 (see Fig. 111) a series ot live levers 6ta to 64;e are pivoted on shoulder screws on arm 66, the tip 67 oit levers 64a to 64;@ (see Fig. 33) are normally inthe space immediately to the lett oit the corresponding cotte-r pins 412. The opposite ends ot' levers 6a@ to 6de have ring tor-med ends 68 {see Fig. 1) which encircle a tube 69 rigidly mounted in trame 70. @n the inside ot tube 69 (see Fig.'y 15) are vmounted tive rods 71a to 71 5 adapted to move longitudinally 'and held' to the left under tension ot a series of springs 72. Fach of the rods 71a to 71e has a pin 73 projecting through slots 74e in cylinder 69 in such a manner that they lie immediately adjacent to the right hand tace ot the ring shaped end 68 otl thepeorresponding levers 6ta to 6de. Fach or the levers 6ta to 6de is under tene sion ot a spring 75 which tends to keep the ring shaped end 68- against the corresponding'pins 73 but does not have suicient -tension to overcome springs 72. Vhen levers 611 to 611e are moved.` to the right, as later described, the tips 67a to 67e ot those levers 6451 to 6de., which* correspond to cotter pins .412 Which have been set, Will engage the set cotter pins and by the motion out their vpivots 65 have the ring shaped ends 68 forced to the right and along with them the corresponding rods 71a to 71e. Those levers 641 to 6de, 1 which correspond to cotter pins, which have not been set, will move in such a manner as to move the corresponding rods 71a to 71e. rlllhe Jfunction of the movementofirods 71ja to 71e will be later described, Arm 66 is rigidlymounted on a shattl76, which is mounted in supports 77 and 78 (see F ig. 15) for longitudinal motion, and is pressed .to the right lunder tension ot spring 79. 'llhe 'forked tip 80 oit a lever 81, (see Fig. 16) pivoted about point 82., engages a groove 83 in the hub ot arm 66. 'Fhe other tip'ot lever 81 engages the end-18d ot a bell cranlr 85, pivot-ed on shoulder screw 86. The other end of bell t* crank '85 carries a roller 87 which engages a caro. 88 tast to a shaft 89. Shaft 89 is rotated once each character vto be trans mitted by means to be later described. As shaft 89 is rotated the high part of cam 88 cornes under roll r 87 rotates bell crank 85., moves. arm about it '.vot' 82, and moves armv -66 .the drm 66 has rigidly 'astenedto its right hand side a ratchet Wheel 90, vvhi has the same number ot teeth es ratchet 58., The teeth of andere ratchet Wheel 90vnorfmally engage a pawl 91 (see Figs. 1 and 4) rigidly mounted in a block 92 fast to cylinder a3. rll`he tension of spring 61 (see Fig. 15) is conveyed through shaft 76, arm 66, ratchet Wheel 90, pavvl 91, block 92, to cylinder 13. When arm 66 and consequently ratchet Wheel 90 are moved to the lett ratchet Wheel 90 will be disengaged from pawl 91 and will engage a pavvl 93, which is mounted in a slot 94- in block 92 and is under tension oit spring 95. llilhen ratchet Wheel 90 engages a pawl 9'3, spring 61 being stronger than spring 95, ratchet Wheel S90-will move and compress spring 95. of ratchet wheel 96 `will he brought opposite paWl 91 and the tips 67'a 67e or" levers 6ta to 6de will be opposite the next row ot cotter pins 42, and, as cam 88 (see Fig. 14) con tinues to rotate, roller 87 will' fall off the high part of cam 88 and allow arm 66 and levers 64a to 64:e to move to the right under tension of spring 79 and rods 71 to 71e Will be set in a combination corresponding to the next row ot cotter pins 42.

By the apparatus so ar described it will be noted that as the shaft 89 is. rotated ratchet 90 and arm 66 will move step by step and the rods 71a to 71e will assume successive combinations of positions corresponding to the setting of successive groups ot' cotter pins 42. rFhe method by which the rods 71l to 71e control the transmission ot the signals will now be described. Gear 20 (see Figs. 6, 11aand 18) is continuouslyrntated by motor 24. 1t carries on oneoside a Cylinder 96. Cylinder 96 and gear 20 are mounted tor rotation on ball bearing 97, the other race of'which is fast to shaft 98. The inside surface oi' cylindei` 96 has three longitudinal grooves 99 (ses Figs. 10, 11 and 12) into which t lugs 100 on a series of rings 101. Mounted on square shaft 96 for rotation. therewith4 is a corresponding series otf discs 102 which alternate with discs 101 and between each disc 101 and disc 102 is mounted a ring 103 free to rotate with either disc 101 and 102. The Stack ot discs 101, 102 and 103 are under tension ot a compression spring 10a. lit will be noted that as gear 20 rotates due to the friction between the discs 101, 102 and 103 there will be tension on shaft 98 tending to rotate it.. @n shaft 98 are mounted two escapement wheels 105 and 106. Fscapement Wheels 105 and 106 `(see Fig. 22) are engaged pallets 107 and 108, respectively, on an anchor 109, which is pivoted about a point 110. The opposite end or anchorf109 is forked and is adapted to engage an impulse pin'111 tast to balance Wheel 112. to balance wheel 112 is hair-spring 113. The parts just described are' the Well known lever Watch escapement in a moditied form. llhe By this motion the next toothl size of hair-spring 113 and balance wheel 112 are so chosen that one-half oscillation of balance wheel 112 corresponds to the time interval of one of the unit impulses which form the signal periods. Balance lwheel 112 carries on its circumference a lug 114 (see Fig. 24) which, when no signals are being transmitted, engages, under tension of hair-spring 113, arm 115, which is pivoted about a point 116. Arm' 11.5 carries a pin 117, which engages a link 118, the other end of which is pivoted about a point 119 to a slide 120, mounted in guides 121 and 122.i Slide 120 is so lmounted in guides 121'and 122 that it can move up and down and out at the' lower end, but cannot move out at lthe upper endsince it is held by lid 123. The upper end of slide 120 has sufficient play in guide 121 so that it can tilt in the guide without binding' when it moves out atthe bottom. Slide 120 and consequently arm 115 arevheld down under tension of a spring 124. When a signal is transmitted, .as later described, \vhich, by means later described, energizes magnet 125, which in turn attracts armav' ture 126 against the tension of spring 127 and causes the tip of arm 128 tov engage the lowerv end of slide 120, and move it upward and along with it link 118 and arm 115, thus releasing balance 112 and through the action of impulse pin 111 and anchor 109 and escapement wheels 105 and 106 shaft 98 will move step-by-step. Just after shaft 98 starts in motion, a cam 129 engages a projection 130 on bell crank 131, pivoted about a point 132, the forked end 133 of which engages pin 117 on arm 115. By the action of cam 129 and arm 131, arm 115 will be heldout of engagement with lug 114, until allow part 134 is opposite projection 130, which will allow arm 115 to again engage'lug 114. By the action of cam-129 shaft 98, having once started to rotate, must complete a half revolution be fore again stoppingand will always be stopped at the end `of the half revolution, until again started by the energizing of magnet 125. It is to be noted (Fig. 13) that escapement 105 has one tooth on each side missing, while escapement wheel 106 has corresponding open spaces filled in. These ,abnormal spaces are so arranged with respect to cam 129 that they come into action' at the time that. arm 115 engages the lug 114 to stop the openrtionof balance' 1 12, so that after balance 112 stops, shaft 98 continues to rotate and causes the last step of shaft 98 to be longer than the others. The llast step of shaft'98 is longer than the others to allow for an interval between the last element of the code and the start impulse of the next succeeding signal, in order to insure the locking of the balance at theI end of a signal and that it shall start afresh at the beginning of the next signal. This long tooth performs the function of a more complicated arrangement described in my U. S. Patent 1,229,201.

As cam 129 rotates it also engages a lug 135, on slide 120 and moves its lower end to the left so that if the magnet 125 is energized continuously the lower end of slide 120 will not be over the tip of arm 128 and can move downward under tension of spring 124 and allow arm 115 to lock balance wheel 112 after lever 131 has been released by cam 129. This device makes possible the operation of a line according to the Morse closed circuit method.v If the line is closed permanently shaft 98 will make one-half revolution and come to rest due tol slide 120 having fallen down back of the projection on arm 128. lf slide 120 did not move outward as described at the bottom, when the line was closed shaft 98 wouldfcontinue to move until the line was again opened.

Shaft 98 carries five cams 136a to 136 (see Figs. 13, 17 and 18) which correspond to the five elements of the code and are spaced 221gL degrees apart or the angular distance through which shaft 98moves during one swing of balance 112. There is also a similar cam 137, which corresponds to the start impulse and is 6712` degrees from the last code cam 136. Corresponding to the cams 136 to 136 is a series of levers 138 to 138 whichy are mounted in guides 139 and 140 and are free to move out at either the top or bottom but are prevented from moving in a vertical direction by a rod 141 which fits in a slot in the upper end of levers 138l to 138. Levers 138a to 138 are under tension at their upper ends of springs 142. Each of the levers 138a to 138 has a projection 143 adapted to be engaged by the corresponding cams 136 to 136. On the ends of the rods 71a to 71 (see Figs. 14 and 33), above described, are plates 144a to 144 So yarranged that when they are in a l position correspondino` to a Cotter pin 42,

which has been pushe in,-they are directly in front of the lower end of a corresponding lever 138a to 138. Plates 144a to 144 which correspond to cotter pins 42, which have notv been operated, will not be `in front of their corresponding levers 138a to 138. Ars` Atheir lower ends a plate 144a to 144 willbe thrust outward at their upper end. It

will be seen then that, as shaft 98rotates, those levers 138 to 138, whichl correspond to set Cotter Ivpins, will be thrust outward is attached to lever 149l by vspring 152.

Directly in front of contact 151 is an adjustable Contact 153. Levers 138a to 138e, through universal bar 145, plunger 146, insulating tip 148, and lever 149, will open and close contacts 151-153 in combinations, corresponding to the setting of the particular group of cotter pins concerned. The

opening and closing 'of contacts 151-153 closes a circuit 'through magnet 125,l in a manner to be later described.

'lhe transmitting apparatus, so far de-v scribed, has concerned itself only with the transmission of those impulses which make up thecode proper. 1n the type of apparatus here described it is necessary to precede each group of code impulses by a so-called start impulse'which acts to start the -mech-- anism into operation for the transmission of each signal. The mechanism for performing this function will now be described. As previously stated, there is mounted on shaft 98 a cam 137 (see Figs. 19, 20 and 21), which is so mounted that, in the normal stopping position of shaft 98, it stops dire'ctly under projection 154 on a lever 155, which is similar to levers 138 to A138e and is also adapted to engage universal `bar 145.' Mounted adjacent to lever 155 is an arm 156, which is pivoted about rod 141,.and has at its lower end a lip 157, extending overthe lower end of lever V155. At the lower. end of lever 156 is a spring 158. `We

will assume that the mechanism'is in the position shown in Figure 21 and that a hook 159 engages another lip 160 on lever 156,

` thus holding it to the right. Hook 159 is mounted for rotation on a shaft 161 and is under tension *of a spring 162, whichv has a tendency to throw 110011159 into engagement with lip 160. Fast to shaft 161 is an arm 163, which is under tension of a spring 164 and tends to turn shaft 161 and, byv

the engagement of a pin 165 fast in shaft 161 with a pin 166 fast in hook 159, thereby lift hook 159 out of engagement with lip 160. Ratchet 90 carries a pin 167, which is so located that it will. engage the tip of lever 163, and move it against tension of spring operation given later.

hook 159 out of engagement with lip 160, allow lever 156 under tension of spring 158 to turn about rod 141, lip 157 will engage the lower end of lever 155 and rock it about cam 137 as a fulcrum, operate universal bar 145, and in turn close contacts 151-153 as previously described. r1`he closing of contacts ll-153 will close the circuit of magnet 125 in a manner to belater described, will operate the start mechanism shown in Figure 24 and previously described, and so startinto motion shaft 98. After shaft 98 has moved a short distance the projection on lever 155 will fall off the high .part of cam 137 and Lwill allow contacts 151-153 to open unless the A code impulse is to be transmitted. 1n which case the circuit will remain closed by the operation of cam 136a as previously described,y and as shaft 98 continues to rotate, contacts 151-1'53 will,-be operated in 'combination correspondingnto the signal to be transmitted. Shaft 98 carries another cam 169, having a high vpart 170, which engages a high part 171 n lever 156 at the beginning of the longstep of shaft 98, previously referred to, and rotates lever 156 about rod 141 and moves it far enough for hook 15 9 to engage projection 160, in case pin 167 1s engaging arm 163. lf,'however,

pin 1674 does not engage arm 163, hook 15.9 will be held out of engagementwith lip 160 and just as shaft 98 comes to rest projection 171 will fall olf the high part 170 of cam 169, and contacts 15. 1-153 will be again closed to send the start impulse for the next signal. Bythe mechanism just described, the transmitting mechanism and also the timing mechanism are allowed to operate according to whether signals are stored on cylinder 43 or not. :Howthis is done will be understood from the description olf the Mounted on shaft 98 is another cam 172 (see Fig. 26) having high part 173, which operates lever 17 4, just before shaft 98 comes to rest. Lever 174 is pivoted about'a point 175, and engages at its other end bell crank` 176, whose other arm 177, under tension of 4a spring 179, is adapted to', engage' alug 17 8, on a roller carrier 18,0, which is similar in every respect to roller carrier 27. previously described. (See Fig. 25).` Corresponding to roller carrier 180 is a drum 181, eccentricf182, spring 183, all similar toA the corresponding parts of the roller clutch shown in Figures 7 and 8. When arm 174 is operated by projection 173, just as shaft t 98 comes to rest, tip 177 is disengaged from lug 178 and 'drum 181, throughroller 184, is locked to eccentric 182, since drum 181 isjfast to a gear 185, which is meshed'with gear 21 and is therefore rotating continuously, shaft 89, which carries cam 88, will be setin motion (see Fig. 14). tions performed by the operation of shaft 89 has lbeen previously described in detail.

By the mechanism, just described, each time shaft 98 rotates and just before it comes to rest, shaft 89` will be started into rotation and will make one revolution. 1n so doing cam 88 will engage roller 87 and through lever 85 rock lever 81, and in turn give arm 66 an out and Iin motion and thereby will cause levers 12a to 12e to engagethe next succeeding set of cotter pins 42 and set platee 144a to 144e in the proper combination to transmit the next signal. ltwill be seen then, that the arm 66 will automatically engage succeeding groups of cotter pins, set plate's 144tl to 144e according to the succeeding combinations and will close contacts 151-153 in combinations corresponding to the combinations of cotter pins set.

In order to explain more clearly lthe successive operations as the machine is used we'shall assume that the machine starts with noA characters stored in the cylinder 43. When in such a state the arm 66 will be `in such a position that the tips ot' the levers 64a to 64@ will be opposite the row of Cotter pins 42al and at the same time pin 167 will engage arm 163 and hoo`k 159 will engage projection 160 as shown in Fig. 21 and lever 156 will be prevented from operating s0 that contacts 151-153will be open. lf a key 7 is depressed the row of cotter pins 42 (F ig. l) will be set as previously described, in a combination corresponding to the key depressed, and the cylinder 43 will be spaced, also as previousl described, so that the row of Cotter pins 42 Fig. 1) will occupy the posi- .tion previously occupied by the cotter pins 42a. When the cylinder 43 is spaced in a right hand direction (Fig. 1) ratchet wheel 90,1through pawl 91, is carried in the vsame direction and along with it the arms 64a to 64 so that they ,will nowoccupy a position corresponding to the position 42b in Fig. 1. `When ratchet wheel 90-is carried forward as described in the previous sentence, pin l167 paragraph. It will be seen that if no characters are stored in the cylinder and a key is depressed the corresponding signal will be immediately transmitted just as though the' keyboard was a direct transmitter.

If, however, immediately after the key 7 has been depressed and before the corresponding signal laas been transmitted Aanv other key is depressed the corresponding row of cotter pins will be set, the cylinder 43 will be spaced in a clockwise direction one space and along with it ratchet wheel 90 and arms 64a to 64e. At the same time the transmission ot the character corresponding'to the first key depressed will be transmitted and ratchet wheel 9() and arms 64a to 64e will beallowed to move vbackward with respect to cylinder 43 one space after the transmission of each character. As the operation of the machine proceeds the depression of succeeding' keys will advance cylinder 43 and arms 64a to 64e step by step in a clockwise direction at a certain rate and at the same time the transmission of succeeding' characters will proceed and the arms 64a to 64e will be moved in a counter clockwise direction with respect to cylinder 43 at a rate depending upon the rate of the balance wheel 112. llt' the operator is working at a greater rate than the rate of transmission the cylinder 43 and arms 64a to 64e will be moved in a clockwise direction at a rate which is equal to the difference between the rate of the operator and the rate of transmission. If the operator stops or goes at a rate slower than the rate of transmission arms 64a to 64e will move in a counter clockwise direction with respect to cylinder 43` 1f the operation of the keyboard is stopped entirely arms 64a to 64e will continue to move in a counter clockwise directionwith respect to cylinder 43 until all the characters are transmitted and all the parts are returned to the position indicated at the beginning of the preceding chapter.

The natural tendency ofa keyboard operacters at a rate faster than the rate of trans- `m1ss1on which will compensate for the times she will operate at a slower rate or stop altogether.

At sub-station X (see Fig. 34) the motion of shaft 98 is timed by the balance and escapement above described. The apparatus at central which reives these signals has a shaft 186 which is provided with a balance and escapement identically like that shown in Figure 22, and also a start mechanism identically like that shown in Figure 24 and is started into operation by the start impulse which operates magnet 187 simultaneously with the starting of the shaft 98 atl substation X. `The balance and escapements at the two stations serve to time the individual impulses forming the signals and the operation of the individual elements of the receiving apparatus, and the st-art impulse performs the 'function of starting the two apparatuses in the same phase position at the beginning of each signal.

The apparatus on the trunk line is continuously synchronized. At station M there is a motor 188 carrying an insulated brush arm 189, upon which are mounted two trailer brushes 190 and 191. There is also provided a timing fork 192. between whose prongs is mounted a magnet 193, the tuning fork carries a plate 1.94-, which oscillates be.- tween the twov contacts 195 and 196, which in turn are connected to alternate segments of segmented ring 19T. The tuning fork is kept in vibration by magnet 193, whose circuit may be traced as follows: positive, through resistance 198, magnet 198, contact 199. plate 19-1, to negative. Magnet 193 attracts the prongs of timing fork 192, breaks the circuit at contact 199, allows the prongs to return, and, by continued repetition of the same operations, keeps the fork in continuous vibration. lVllile the tuning fork 192 is oscillating between contacts 195 and 196, motor 188 is driving trailer brushes 190 and 191 over segmented ring 19T and collecting ring 200, and opening and closing a shunt circuit around resistance 201 at rapidly recurring intervals, so that motor 188 will receive a variable amount of current, depending upon the phase position of the/ tuning fork and of the rotating trailer brush 190 with respect to segmented ring 19T. T he period of vibration of the fork 192 is so chosen that motor 188, when in synchronism with the fork, will drive trailer brush 190l from the middle of one segment to the midlle of the next segment on commutator 197 in the time of one-half vibration of fork 192.

At central M1 (see Fig. for driving,

ated from the reversals of the line current.

The signa-ls sent out from station M, as later described, keep in vibration main line relay 206. Tongue 207 vibrates between two contacts 208 and 209 which connect, respectively, toplus and minus, through resistances 210 and211 and also to Yone terminal of two condensers 212 and 213. The other terminals of condensers 212 and 213 are connected together and to one terminal of tuning fork magnet 214, the other terminal f which connects to tongue 207. At each reversal of the line current thecondensers 212 and 213 will discharge through magnet 214- and give it a vibrating impulse. As in the case of the apparatus at central M, brush ,arm 205 will rotate in phase with the vibrations of tuning fork 208, and due to the fact that tuning fork 203 is vibrated byA impulses sent out from central M it will be in phase with tuning fork 192 and therefore brush arms 189 and 205 will rotate in synchronism. The operation of this synchronizing device is more fully described in my S. Patent 1,201,621.

For each revolution of br'ush arm 258 ten impulses are sent to line. Five of these impulses are used for the transmission here described, the remainingfive could be used for transmission from another substation, for example, substation Y in Fig. 36. The segmeiited rings 19T and 204i have twenty segments. or twice as many as the number of impulses sent out'on the line during one revolution. This is necessary in order that tuning fork 203 may be in the same phase position each time the line current is reversed. The reason for this is more fully explained in my said S. Patent No. 1,201,621. The normal current sent Out on the line when no code signals are being sent is plus for one quadrant and minus for the other quadrant. The normal current is shown in Fig. 40. All the curves show the current for a period corresponding .t0 the time for two revolutions of the distributors. By this means there are always reversals on the line to maintain the synchronism, otherwise synchronism would be lost if, for any considerable interval, no signals were transmitted.

ln my co-pending application, Serial No. 286,540, l have shown a method for the operation 4of substations by a non-synchronous method and the trunk 'line by a synchronous method, in which it is necessary that there shall be a definite relation b'etween the timing device (balance and escapement in this case) of the apparatus at the substatioii for operation over the branch line and the timing device (tuning fork in this case) of the apparatus at the central station for operation over the trunk line. In the present case no such relation is essential. 1t is only necessary that the apparatus operating over the branch line shall be adapted to operate at least as fast as the apparatus on the trunk line. interfering with the operation. The rate of transmission of the signals (number per minute) over the branch line is, however, determined by the apparatus on the trunk line.

At central M1 shaft 215 has a balance and eseapement and a start mechanism similar to that shown in Figures 22 and 24, and a magnet 216 which corresponds in its function to magnet A125 at substation X. At substation Xl' there is similarly a shaft 217, 'which' also has a'balance and escapement,

and start mechanism similar to that in Fi ures 22 and 24 to time the operation of sh'at 217, and a magnet 218 similar to magnet 125, which start shaft 217 into operation.

lt can be any amount faster without' relance The timing of the various parts of the mechanism at the different stations having been described. the description will again be taken up at substation X. At substation X magnet 125 has one terminal connected through resistance 219 to positive and the other terminal to forward contact 220 of neutral relay 221, the tongue 222 of which is connected t negative. Magnet 223 of relay 221 has one terminal connected to ground, the other terminal connected to contact 151. Contact 153 connects to branch line 224 which connects to one terminal of magnet 225 0f neutral relay 226 located at cent-ral M. The other terminal of magnet 225 connects through contacts, to be later described, to resistance 227 to the positive pole of generator 228, the other pole of which connects to ground. Assuming the contacts at station M in line 224, which have not yet been described,to be closed, the initial closing of contacts 151-153 by the start impulse mechanism .at substation X, already described and sho-wn in Figures and 21, energize magnet 223. closes contacts 220-222, energizes magnet 125, starts in motion shaft 9'8, and, as shaft 98 rotates st'ep-by-step, line224 will be closed through contacts 151-153 in combinations corresponding to the combination of cotter pins 42 which at that time engage levers 6421 to 64e. At the same time contacts 229 and 230 of relay 226 will close. rl`he closing 0f contacts 229-230 will close a circuit as follows.: from positive to resistance 231, magnet 187, contact 229, tongue 230, to negative. Armature 232 will be operated and shaft 186 will be started into operation simultaneouslywith shaft 98 at substation X and timed b the mechanism previously referred t0. Shaft 186 carries a series of cams 233a to 233e similar to cams -234a to 234e on shaft 98 (see Fig. 13), and likewise spaced 221; degrees apart. rlhe series of cams 234a to 234er have been shown as onv shaft 98 i'n- Fig. 13 to show their relation to other cams, though they are not shown as used at substation X. lt is usual', however, in allthe machines to include both sending and receiving cams. rl`h`e receiving cams on I a sending machine are frequently used to inake a home record. lt will be noted that these cams are pointed, while cams 1361to 136e" have considerable face. rthis is done in order that the receiving cams shall use only central or good portions of the received irnpulses and thus increase the margin of opvers 235 to 235e are held in place by individual springs 239. As shaft 186 rotates stepbystep levers 235a to 235e are thrust out in succession, and if, at the moment when they are thrust outward, the pointed tips 240 of armature 232 are down or below pointed projections 241 on levers 235a to 235e levers 23511 to 235e will be pushed out at the bottom and will return immediately to their normal position, after cams 233a to 233e pass from under projections 242. lf, however,.when cams 233a t0 233e thrust levers 235a to 235e outward magnet 187 is energized, pointed projections 240 are above tip 241 levers 235a to 235e are prevented from moving out at the bottom and will move out at the top against tension of spring 239. When levers 235a to 235e move outward at the top, plungers 244 are thrust upward by springs 245 and engage notches 246 (see Fig. 32) in the upper ends of levers 235a to 235e, and lock levers 235n to 235e in their outward position. Levers 235a to 235e carry on their upper ends insulating. projections 247 which engage contact springs 248a to 248e. When `levers 235a to 235e are in their back positions contacts 248a to 248e will engage contacts 249a to 249e. lf, however, levers 235a to 235e are in their outward positions contacts 248 to 248e will make contact with contact springs 250a to 250e.

As shaft 186 rotates, levers 235a to 235e, and in consequence contact springs 248a to 248e will be operated and set in a position corresponding to the code signal received by relay 226. All of the back contacts 249a to 249e are connected together and through resistance 251 (see Fig. 34) to the positive pole of generator 252, the other pole of which is connected to ground. All of the front contacts 250 to 250e are connected together and through a resistance 253 to negative pole of' generator 254, the other poleY of which is connected t0 ground. Movable contacts 248x11 to 248e are connected to segments 255a to 255e of segmented ring 256 upon which bears trailer brush 257, carried by arm 258, `which is fast to but insulated from arm 189, arm 258 carries another trailer brush 259 which bears on collecting ring 260..

Collecting ring 260 is connected to main line 261. As brush arm258 is rotated by motor 188 positive or negative current will be transmitted from generator 252 or 254 through resistance 251 or 253, tongues 248a to 248e, segments 255a to 255e, trailer 257, arm 258, trailer 259, collecting ring 260, main line 261, main linerelay 206, main line relay 262, to ground.` By the operation of the apparatus so far described, relaysY 206 and 262 will be operated in code combina'- tions corres ending to the combination of cotter pins 42 engaging levers 64a to 64e. rlhe signal corresponding to the setting'of contact springs 248a to 248e, having been transmitted, it is necessary t0 return levers 235u to 235e totheirnormal position ready for the reception of the next code signal. The mechanism for accomplishing this will now be described. Extending immediately above all the plungers 244 is one arm of a bell crank 263, pivoted about a point 264. Mounted adjacent to the other arm and adapted to operate it is a magnet 265. The circuit of magnet 265 may be traced as follows: positive, resistance 266, magnet 265, contact 267, tongue 268 of neutral relay 269 to negative.` The circuit of the coil of relay 269 may be traced as follows: positive, resistance 270, coil of neutral relay 271 (the function of this relay will be described later), coil Iof neutral relay 269, segment 272 of segmented ring 273, trailer brush 274, brush arm 275 which is rigidly fastened to but 4insulated from brush arm 189, trailer brush 276, collecting ring 277 to negative. lt will be noted that, by this arrangement, just after trailer brush 257 has passed segment 255e and consequently transmitted the last impulse of the signal, the above circuit will be completed, magnet 265 will be energized, bell crank 263 operated, and all of the levers 235a to 235e returned to their normal position ready for kthe next signal.

When describing the. transmission from substation X it was assumed that the line at' M was closed permanently. This, however, is not the case. llt is necessary that the apparatus at substation Xshall start with a definite phase relation with respect to the receiving apparatus at M. l This is accom- 'plished by keeping the circuit at M open and not allowing the start impulse to be sent until the proper phase position is reached.

The apparatus for. accomplishing this will now be described. 'llhe tongue 278 and forward contact 279 of relay 271 are connected respectively to/contactsv 280 and 281 and 'are both 'connected in series in line 224 so that either one may close the line. By the closing of the circuit abovel described, just after the E impulse has been transmitted on the trunk line, relay`271 is voperated and line 224 is closed through contacts 278 and 279, and,if the line is also closed at the substation X, shafts v98 and 186 will .both be started in motion for the transmission and .reception of a signal on line 224. llf, however, 'the line is open at substation X neither shaft will be started in motion. Even when 'contacts 15.1 and 153 at substation X are closed, the apparatus at neither station will' start until trailer brush 274 reaches segment 272. By this means a detinite phase relation' start impulse'.

and will maintain branch line 224 closed at station M until the complete signal has been received. It will be vnoted that thereA is a connection tapped to a point between coils of neultral relays 269 and 271and connected to segment 285 immediatelyV following segment 272. rlhis connection causes relay 271 to close its contact longer than relay 269 andinsures contacts 278-279 staying closed until contacts 280-281 close.

The signals transmitted on line 261 operate relay 262 and move tongue 286 between contacts 287 and 288 upon the reversal of the current in line 261. Contacts 287 and 288 connect to points 289 and 290 on resistance 291, bridged between the positive and negative direct current terminals. Point 292 lmidway between 289 and 290 connects to ries another trailer brush 299, which rides on collectingring 300, connected to tpngue 286 of relay 262. s brush' arm 298 rotates i in step with transmitting brush arm 258 at station M, impulses Iwill be transmitted through the relays 294a to 294e, according to whether positive or negative impulses are transmitted on line 261. lf positive or normal. impulses are transmitted, tongues 301a to 301e will receive impulses toward. their back stops and any relay correspondinglto a negative impulse on line 261 will receive an impulse toward its front stop, so that the relays 294a to 294e will have their tongues set according to the impulsesA transmitted on line 261. If all of the. relays 294L to 294e receive normal or positive impulses, relay 293 Will have its tongue 302 pulled toward.

its back stop. lf, however, any of the relays 294a to 294e receive a negative or setting im'- pulse, tongue 302 will be moved to its front stop 303. Relay 293 serves to control the An additional polarized relay 293a is provided to control the start impulse. If rela 293 is moved against its forward contact y A, B, C or D impulse and the E impulse is normal the tongue of relay 293 will be carried to its bac-k stop. Relay 293a serves the purpose of storing up any forward. impulse received by relay 293 until it has performed its function; The forward coil of relay 293la has one terminal connected through resistance 293 to positive and its other terminal to forward contact 303 of relay 293. Tongue 302 of relay 293 is connected to negative. receives an impulse to throw its tongue l/Vhen relay 293' against its forward contact 303 an impulse is transmitted to relay 293"l through a circuit traced as follows: positive supply main resistance 293", forward coil of relay 293` contact 303, tongue 302 to negative. Tongue 293" is thrown against forward contact 293d and completes a circuit described below.

The impulses cannot be transmitted directly from the contacts of relays 294n to 294", since it is not possible to get such a relation between the receiving and transmitting sunflowers that the transmission Will not be interfered with by the setting of the relays for the next signal. There is provided therefore an auxiliary set of polarized relays 304il to 304e and an auxiliary start polarized relay 305. The tongues of the relays 294l to 294c are connected to the common wire of the forward and back coils of the auxiliary relays 304b to 304e amd the common terminal 4of the forward and back coils of relay 304a is connected to one terminal of the forward coil of relay 305. The remaining terminals of the forward and back coils of relay 304u to 304e are connected to the forward and back contacts 306a to 306e, amd 307a to 307e, respectively, of relays 294il to 294e. Just after the E primary relay 294@ has received its impulse, an impulse is transmitted to the auxiliary relays through a circuit traced as follows: positive supply main, resistance308, tongue 301e, Contact 306e or 307e, back or forward coil of relay 304e, depending upon whether a normal or setting impulse is transmitted for the E element, tongue 3061, and ina similar manner through the remaining relays 304cl to 3043, forward coil of relay 305, c ontact 2931, tongue 293, segment 309, trailer brush 310, brush arm 311, trailer brush 312, collecting ring 313, to negative. An impulse will be transmitted through the above circuitonly when code impulses are transmitted on line 261 and the impulse will immediately follow the E impulse on line 261. Whenever all the inipulses transmitted on line 261 are normal, relays 293 and 293*L will not`be operated and consequently the above describedcircuit will be open. The relays 304a to 304E will remain set corresponding to the combination of the last character transmitted and relay 305,'will not be operated.

The relays 294a to 294e are operated in succession, while the relays 304a to 304e are by a'A single.A impulse set in combination correspending to the combination of relays 294a to 294e set. llt will be noted that there are no parallel connections and that each relay receives a definite impulse to return it to normal or to set it, so that there is required only one contact on the distributor and the relays 304 x` to 304e are set the maximum length of time. The relays 304zt to 304e are sometimes called overlap relays in that they allow a combination to remain set while the next signal is being received. This arrangement gives the maximum overlap.

Shaft 215 carries a series of transmitting cams 314a to 314e (see Figs. 30 and 31) similarl in every respect to the cams 136;l to 136e on shaft 98 at station X. Corresponding to each of the cams 314at to 314e and mounted in guides 315 and 316 is a series of levers 317 to 317e corresponding exactly to the series of levers 138n to 138e. Levers 317*11 to 317e, however, instead of operating a universal bar, each individually operate through insulating tips 318, contacts 319a to 319e and 320a to 320e. There is also a lever 321, which corresponds exactly to start lever 155, and a pair of contacts 322 and 323 operate thereby. Levers 321 and 317a to 317e, however, differ from the corresponding levers and 1383A to 138e in that they are permanently prevented from moving at their lower ends by rod 324, so that the contacts 319a to 319e are all operated in succession whenever shaft 215 is rotated and cont-acts 322-323 are always closed in the-normal stopping' position of shaft 215.

' l/Vhenever relay 305 is thrown against its forward stop a circuit may be traced as follows: positive terminal of generator 325, resistance 326, contact 322, contact 323, contact 327, tongue 328, coil of relay 329, branch line 330, neutral relay 331, to ground. The energizing of the coil of relay 329 throws tongue 332 against its forward stop 333 and completes a circuit as follows: positive terminal, resistance 334, magnet 216, contact 333, tongue 332 to negative. The energizing of ma net 216 operates its corresponding start mec anism, as previously described, and starts shaft 215 in motion and, as it moves, impulses will be transmitted on line 330 from positive terminal of generator 325,

through resistance 326, contacts 3193 to 319 and 320a to 320e, contacts 335u to 335e, tongues 336a to 336e, depending upon whether or not the particular impulse is to be transmitted.

Tt will be observed that all the relays 293, 294aL to 294e and 304a to 304e receive impulses at every revolution of brush arms 298 and 311 which set them or return them to normal so that no special arrangement is impulse as follows: positive supply source, resistance 337, normal coil of relay 305, nori mal coil of relay 293, segment 338, trailer brush 310, arm 311, trailer brush 312, collecting ring 313 to negative. Segment 338 is located just ahead of the impulse segment.

vllft will be noted that on line 261 'only the code impulses proper were transmitted, while on line 330 each group of code impulsesl is preceded by a start impulse under control of relays 293 and 305. 

